Centrifugal separator with presedimentation means

Abstract

The centrifugal rotor contains a distributor forming a conical wall having openings through which the central inlet chamber is connected to the separating space, the inlet chamber also being connected through a presedimentation space to a peripheral sludge space by way of an annular slot located radially outward from said openings. An annular flexible valve for the slot has one side directed toward the presedimentation space and an opposite side directed toward the peripheral sludge space, the valve being operable to close said slot when subjected to substantially equal liquid pressures on said sides thereof and to open the slot upon creation of a substantial pressure difference on said sides in response to opening of outlets from the peripheral sludge space.

We claim: 
     
       1. A centrifugal separator comprising a rotor forming a separating space and also a peripheral space for receiving separated sludge from the separating space, the rotor having peripheral outlets for discharging the separated sludge, a valve bowl movable axially in the rotor to open and close said sludge outlets, a stack of conical separation disks in said separating space, the rotor having a central inlet chamber for receiving a sludge-containing mixture to be centrifuged, a distributor forming a conical wall having openings through which said inlet chamber is connected to said separating space, the rotor also having opposed annualar surfaces fixed relative to the rotor and forming between the surfaces an annular slot through which said inlet chamber is connected to said peripheral sludge space independently of said wall openings, there being a presedimentation space located radially outward from said openings and leading from said inlet chamber to said annular slot, and annular flexible valve means for said slot, said valve means being fixed to the rotor and having one side directed toward the presedimentation space and an opposite side directed toward the peripheral sludge space, said valve means being operable to close said slot when subjected to substantially equal liquid pressures on said sides thereof and to open said slot upon creation of a substantial pressure difference on said sides in response to opening of said sludge outlets. 
     
     
       2. The separator of claim 1, in which said valve means consists of a flat rubber ring. 
     
     
       3. The separator of claim 1, in which one of said opposed annular surfaces is formed by a conical disk member which is fixed relative to the rotor and located at the opposite side of said conical wall from said separating space, said disk member partly defining said presedimentation space, said valve means having a radially inner edge portion along which the valve means is fixed to said disk member. 
     
     
       4. The separator of claim 1, comprising also sleeves surrounding said conical wall openings and projecting from said wall in the direction away from the separating space. 
     
     
       5. The separator of claim 1, in which said conical wall has an outer edge partly defining an annular passage through which said annular slot communicates with the peripheral sludge space.